At full size, these small fish are around 10cm and although dull from a distance, they have vivid horizontal coloured stripes stretching along their body. Males and females can be distinguished fairly easily by their colouration; males tend to be brighter and have distinctive pale orange edges to the tail, while the female’s tail has a darkened tip (see photo below).
Jumping guabines are found throughout T&T as well as in northern Venezuela. They thrive in a variety of habitats, from muddy road-side puddles to the shallow edges of large rivers.
As the name suggests, this fish has the ability to launch itself completely out of the water. The ability to beach yourself may not seem like much of an evolutionary advantage, but this fish has another trick up its sleeve – it can breathe atmospheric air through its tail, which is covered in capillaries. As such, a jumping guabine can ‘jump’ out of water onto land and survive for a considerable time, as long as it does not dry out entirely.
This allows these fish to travel short distances over land to new bodies of water, and it is not unusual to find a few individuals in isolated puddles, often some distance away from permanent water. In fact, Dr Doug Fraser, of Siena College, New York, has been studying jumping guabine movements in the Northern Range for many years, along with various colleagues. They have discovered that jumping guabine seem to have something akin to a ‘personality’, which determines whether they prefer to be ‘shy stay-at-homes’ or ‘bold explorers’. In other words, they found that fish with a bolder personality are more likely to travel long distances from their home.
Another advantage of jumping is that it allows hungry individuals to hunt prey that may be otherwise out of reach - on overhanging vegetation or at the water’s edge, such as ants [see photo]. Incredibly, they have been recorded jumping as high as 14cm, more than their total body length, to catch prey. While in the water, they are ravenous predators of small aquatic invertebrates, small fish and tadpoles. As a result, in an example of excellent parenting, Trinidad stream frogs, Mannophryne trinitatis, will always check for jumping guabine before depositing their tadpoles in a pool to ensure the safety of their young.
This speedy response not only helps them to catch prey but also to avoid becoming prey themselves. I recently witnessed a large spider (Ancylometes bogotensis) capture an adult jumping guabine from the water’s edge, so it is not only fish and bird predators they have to stay alert for!
It is easy to overlook some of our most common wildlife species, because we see them so frequently. However, with this fish, the very fact that it is found everywhere is what makes it fascinating. Next time you see a jumping guabine, take a closer look – is she a dull bold-explorer or is he a colourful stay-at-home?